Commit 6890896b authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Alexei Starovoitov
Browse files

bpf: Fix missing bpf_base_func_proto in cgroup_base_func_proto for CGROUP_NET=n 

linux-next build bot reported compile issue [1] with one of its
configs. It looks like when we have CONFIG_NET=n and
CONFIG_BPF{,_SYSCALL}=y, we are missing the bpf_base_func_proto
definition (from net/core/filter.c) in cgroup_base_func_proto.

I'm reshuffling the code a bit to make it work. The common helpers
are moved into kernel/bpf/helpers.c and the bpf_base_func_proto is
exported from there.
Also, bpf_get_raw_cpu_id goes into kernel/bpf/core.c akin to existing
bpf_user_rnd_u32.

[1] https://lore.kernel.org/linux-next/CAKH8qBsBvKHswiX1nx40LgO+BGeTmb1NX8tiTttt_0uu6T3dCA@mail.gmail.com/T/#mff8b0c083314c68c2e2ef0211cb11bc20dc13c72



Fixes: 0456ea17 ("bpf: Enable more helpers for BPF_PROG_TYPE_CGROUP_{DEVICE,SYSCTL,SOCKOPT}")
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200424235941.58382-1-sdf@google.com
parent 745abfaa

include/linux/bpf.h

+8 −0
Original line number Diff line number Diff line
@@ -1215,6 +1215,7 @@ int btf_check_type_match(struct bpf_verifier_env *env, struct bpf_prog *prog, 


struct bpf_prog *bpf_prog_by_id(u32 id);



const struct bpf_func_proto *bpf_base_func_proto(enum bpf_func_id func_id);

#else /* !CONFIG_BPF_SYSCALL */

static inline struct bpf_prog *bpf_prog_get(u32 ufd)

{
@@ -1365,6 +1366,12 @@ static inline struct bpf_prog *bpf_prog_by_id(u32 id) 
{

	return ERR_PTR(-ENOTSUPP);

}



static inline const struct bpf_func_proto *

bpf_base_func_proto(enum bpf_func_id func_id)

{

	return NULL;

}

#endif /* CONFIG_BPF_SYSCALL */



static inline struct bpf_prog *bpf_prog_get_type(u32 ufd,
@@ -1531,6 +1538,7 @@ const struct bpf_func_proto *bpf_tracing_func_proto( 
/* Shared helpers among cBPF and eBPF. */

void bpf_user_rnd_init_once(void);

u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);

u64 bpf_get_raw_cpu_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);



#if defined(CONFIG_NET)

bool bpf_sock_common_is_valid_access(int off, int size,

include/linux/filter.h

+0 −2
Original line number Diff line number Diff line
@@ -863,8 +863,6 @@ int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog); 
int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,

			      bpf_aux_classic_check_t trans, bool save_orig);

void bpf_prog_destroy(struct bpf_prog *fp);

const struct bpf_func_proto *

bpf_base_func_proto(enum bpf_func_id func_id);



int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);

int sk_attach_bpf(u32 ufd, struct sock *sk);

kernel/bpf/core.c

+5 −0
Original line number Diff line number Diff line
@@ -2136,6 +2136,11 @@ BPF_CALL_0(bpf_user_rnd_u32) 
	return res;

}



BPF_CALL_0(bpf_get_raw_cpu_id)

{

	return raw_smp_processor_id();

}



/* Weak definitions of helper functions in case we don't have bpf syscall. */

const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;

const struct bpf_func_proto bpf_map_update_elem_proto __weak;

kernel/bpf/helpers.c

+73 −0
Original line number Diff line number Diff line
@@ -562,3 +562,76 @@ const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto = { 
	.arg3_type      = ARG_PTR_TO_UNINIT_MEM,

	.arg4_type      = ARG_CONST_SIZE,

};



static const struct bpf_func_proto bpf_get_raw_smp_processor_id_proto = {

	.func		= bpf_get_raw_cpu_id,

	.gpl_only	= false,

	.ret_type	= RET_INTEGER,

};



BPF_CALL_5(bpf_event_output_data, void *, ctx, struct bpf_map *, map,

	   u64, flags, void *, data, u64, size)

{

	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))

		return -EINVAL;



	return bpf_event_output(map, flags, data, size, NULL, 0, NULL);

}



const struct bpf_func_proto bpf_event_output_data_proto =  {

	.func		= bpf_event_output_data,

	.gpl_only       = true,

	.ret_type       = RET_INTEGER,

	.arg1_type      = ARG_PTR_TO_CTX,

	.arg2_type      = ARG_CONST_MAP_PTR,

	.arg3_type      = ARG_ANYTHING,

	.arg4_type      = ARG_PTR_TO_MEM,

	.arg5_type      = ARG_CONST_SIZE_OR_ZERO,

};



const struct bpf_func_proto *

bpf_base_func_proto(enum bpf_func_id func_id)

{

	switch (func_id) {

	case BPF_FUNC_map_lookup_elem:

		return &bpf_map_lookup_elem_proto;

	case BPF_FUNC_map_update_elem:

		return &bpf_map_update_elem_proto;

	case BPF_FUNC_map_delete_elem:

		return &bpf_map_delete_elem_proto;

	case BPF_FUNC_map_push_elem:

		return &bpf_map_push_elem_proto;

	case BPF_FUNC_map_pop_elem:

		return &bpf_map_pop_elem_proto;

	case BPF_FUNC_map_peek_elem:

		return &bpf_map_peek_elem_proto;

	case BPF_FUNC_get_prandom_u32:

		return &bpf_get_prandom_u32_proto;

	case BPF_FUNC_get_smp_processor_id:

		return &bpf_get_raw_smp_processor_id_proto;

	case BPF_FUNC_get_numa_node_id:

		return &bpf_get_numa_node_id_proto;

	case BPF_FUNC_tail_call:

		return &bpf_tail_call_proto;

	case BPF_FUNC_ktime_get_ns:

		return &bpf_ktime_get_ns_proto;

	default:

		break;

	}



	if (!capable(CAP_SYS_ADMIN))

		return NULL;



	switch (func_id) {

	case BPF_FUNC_spin_lock:

		return &bpf_spin_lock_proto;

	case BPF_FUNC_spin_unlock:

		return &bpf_spin_unlock_proto;

	case BPF_FUNC_trace_printk:

		return bpf_get_trace_printk_proto();

	case BPF_FUNC_jiffies64:

		return &bpf_jiffies64_proto;

	default:

		return NULL;

	}

}

net/core/filter.c

+1 −77
Original line number Diff line number Diff line
@@ -256,17 +256,6 @@ BPF_CALL_2(bpf_skb_load_helper_32_no_cache, const struct sk_buff *, skb, 
					  offset);

}



BPF_CALL_0(bpf_get_raw_cpu_id)

{

	return raw_smp_processor_id();

}



static const struct bpf_func_proto bpf_get_raw_smp_processor_id_proto = {

	.func		= bpf_get_raw_cpu_id,

	.gpl_only	= false,

	.ret_type	= RET_INTEGER,

};



static u32 convert_skb_access(int skb_field, int dst_reg, int src_reg,

			      struct bpf_insn *insn_buf)

{
@@ -4205,26 +4194,6 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = { 
	.arg1_type      = ARG_PTR_TO_CTX,

};



BPF_CALL_5(bpf_event_output_data, void *, ctx, struct bpf_map *, map, u64, flags,

	   void *, data, u64, size)

{

	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))

		return -EINVAL;



	return bpf_event_output(map, flags, data, size, NULL, 0, NULL);

}



const struct bpf_func_proto bpf_event_output_data_proto =  {

	.func		= bpf_event_output_data,

	.gpl_only       = true,

	.ret_type       = RET_INTEGER,

	.arg1_type      = ARG_PTR_TO_CTX,

	.arg2_type      = ARG_CONST_MAP_PTR,

	.arg3_type      = ARG_ANYTHING,

	.arg4_type      = ARG_PTR_TO_MEM,

	.arg5_type      = ARG_CONST_SIZE_OR_ZERO,

};



BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,

	   int, level, int, optname, char *, optval, int, optlen)

{
@@ -5983,52 +5952,7 @@ bool bpf_helper_changes_pkt_data(void *func) 
	return false;

}



const struct bpf_func_proto *

bpf_base_func_proto(enum bpf_func_id func_id)

{

	switch (func_id) {

	case BPF_FUNC_map_lookup_elem:

		return &bpf_map_lookup_elem_proto;

	case BPF_FUNC_map_update_elem:

		return &bpf_map_update_elem_proto;

	case BPF_FUNC_map_delete_elem:

		return &bpf_map_delete_elem_proto;

	case BPF_FUNC_map_push_elem:

		return &bpf_map_push_elem_proto;

	case BPF_FUNC_map_pop_elem:

		return &bpf_map_pop_elem_proto;

	case BPF_FUNC_map_peek_elem:

		return &bpf_map_peek_elem_proto;

	case BPF_FUNC_get_prandom_u32:

		return &bpf_get_prandom_u32_proto;

	case BPF_FUNC_get_smp_processor_id:

		return &bpf_get_raw_smp_processor_id_proto;

	case BPF_FUNC_get_numa_node_id:

		return &bpf_get_numa_node_id_proto;

	case BPF_FUNC_tail_call:

		return &bpf_tail_call_proto;

	case BPF_FUNC_ktime_get_ns:

		return &bpf_ktime_get_ns_proto;

	default:

		break;

	}



	if (!capable(CAP_SYS_ADMIN))

		return NULL;



	switch (func_id) {

	case BPF_FUNC_spin_lock:

		return &bpf_spin_lock_proto;

	case BPF_FUNC_spin_unlock:

		return &bpf_spin_unlock_proto;

	case BPF_FUNC_trace_printk:

		return bpf_get_trace_printk_proto();

	case BPF_FUNC_jiffies64:

		return &bpf_jiffies64_proto;

	default:

		return NULL;

	}

}

const struct bpf_func_proto bpf_event_output_data_proto __weak;



static const struct bpf_func_proto *

sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)

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